Simplify the following expression: $k = \dfrac{6a^2 - 3ba}{2ba - 4ca} - \dfrac{6ba}{2ba - 4ca}$ You can assume $a,b,c \neq 0$.
Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{6a^2 - 3ba - (6ba)}{2ba - 4ca}$ $k = \dfrac{6a^2 - 9ba}{2ba - 4ca}$ The numerator and denominator have a common factor of $a$, so we can simplify $k = \dfrac{6a - 9b}{2b - 4c}$